Formed ceramic bodies, including but not limited to high surface area structures, for example porous honeycomb bodies, may be used in a variety of applications. Such formed ceramic bodies may be used, for example, as supports for catalysts for carrying out chemical reactions or as sorbents or filters for the capture of particulate, liquid, or gaseous species from fluids such as gas streams and liquid streams. As a non-limiting example, certain high surface area materials, such as, for example, honeycomb-shaped bodies, may be used as catalyst substrates or for the capture of heavy metals from gas streams.
Low coefficient of thermal expansion (“CTE”) ceramics are one category of ceramics used in environmental filtration applications. Two examples of low CTE materials are cordierite and aluminum titanate (“AT”). One process used in the manufacture of ceramic honeycombs involves batching cordierite or AT precursor materials, forming a green body, and reaction sintering the precursor materials to produce the final phase (e.g., cordierite or AT) in situ. This process can lead to the formation of liquids near the top soak temperature, however, as well as considerable shrinkage of the green body due to sintering and reaction of the precursor materials.
In addition, the process using reaction sintering often uses large amounts of pore formers for making high porosity honeycombs. In some embodiments, reduced amounts of pore formers may increase efficiencies and cost reductions.
Finally, the particle size distribution (“PSD”) of the ceramic batch materials plays a key role in realizing the desired microstructure. The process using reaction sintering can require the use of premium grade raw materials in order to obtain the desired microstructure.
Thus, it would be useful to have alternate methods.